Type

URI

College

Program

Department

Degree Level

Date

Metadata

Abstract

I studied the spatial distribution and the demographic structure of the mistletoe
Phoradendron anceps in relation to the distribution of its host (Pisonia albida), in a 5.29
ha plot in the Guánica forest. Both parasite and host species had an aggregated spatial
pattern. The mistletoe spatial pattern was mainly explained by the host size and by
dispersal. Larger Pisonia trees were generally more frequently and intensively parasitized
than smaller trees. Parasitized trees were more prevalent in low-density stands than in
high-density stands. Foraging and feeding behavior of Euphonia musica suggested that it
could be the main disperser of the mistletoe seeds. Seed dispersal appeared to be
distance-limited. The demographic structure of the mistletoe was analyzed by considering
the mistletoe population in the study plot as a metapopulation of mistletoe subpopulations
on individual trees. Subpopulation structures were not correlated with the spatial distance
between them. Six subpopulation structure patterns were identified. Apparently, larger
subpopulations with a high number of reproductive individuals may be the sources of
seeds not only for these subpopulations themselves but also for nearby subpopulations.
The overall mistletoe metapopulation structure suggests that recruitment of young
mistletoes has been relatively continuous over the past few years. The Phoradendron
anceps-Pisonia albida system in Guánica best fits the habitat-tracking metapopulation
model in which the habitat patches are dynamic.